Liquefaction (Meaning and Explanation)

We explain what liquefaction is, its types and differences between physical and chemical change. Also, examples and applications.

What is liquefaction?

Liquefaction or liquefaction is the process of physical change in which a substance in a solid or gaseous state passes directly into a liquid state thanks to a radical change in their physical conditions.

The term is generally used to refer to gases (that is, gas liquefaction), but its use is also common when referring to radical processes of converting solids to liquid that are not commonly capable of doing so.

In the case of gases it is a very common process and of great industrial importance, in which a gaseous body is compressed at very low temperatures forcing its particles to bond in such a way that they acquire a temporary state of liquidity.

This is the method used to transport most gases (since they are much more stable in a liquid state) and is the reason why the gas accumulated in lighters is a liquid: when the ignition mechanism is activated, it decreases. the pressure and part of the liquid returns to its gaseous form, allowing the spark from the lighter to ignite it and feeding a flame.

Types of liquefaction

We can use the term liquefaction in three common contexts:

Gas liquefaction. It is the process of compressing gases at a low temperature to bring them to a liquid state, from which they will emerge spontaneously if we decrease the pressure, or explosively if we increase their temperature.
Soil liquefaction. It is the consequence of seismic movements (intense tremors, even tsunamis), whose energy is such that they can vary the consistency of certain soils and make it similar to that of a heavy liquid or quicksand. This usually triggers avalanches or landslides.
Direct coal liquefaction. It is a very specific use of the term, which refers to a chemical change – not physical, like the previous ones – known as the Pott-Broche process, which converts coal into a mixture of hydrocarbons called “synthetic crude oil”, very similar to oil. The process usually consists, roughly speaking, of mixing coal with solvents at high pressures and temperatures, and then adding hydrogen to the mixture (a process known as “hydrocracking”).

Examples of liquefaction

tsunami liquefaction — Soil liquefaction is the change in soil consistency after an earthquake.

There are many examples of gas liquefaction around us: the liquid content of lighters, gas containers in ovens, liquid oxygen in hospitals, the anesthetic gas used to operate, or even the liquefied natural gas that feeds our kitchens via pipe. All are perfect examples of liquefaction of a gaseous body.

On the other hand, if we want to have examples of soil liquefaction we can search online videos of what happened in some of the big earthquakes recent history. The results are usually impressive.

Liquefaction applications

liquefaction lighter — Liquefaction has multiple industrial uses.

Gas liquefaction has very important applications in the industrial world, to the extent that allows gas to be transported in a safer and more protected way given that in its liquid condition it acquires greater stability, especially when it comes to highly combustible hydrocarbons.

Furthermore, given the ability of gases to be compressed into small volumes, we can fit a large amount of gas into a container, thus justifying the weight and investment in its design and transportation.

Similarly, coal liquefaction and other laboratory processes They allow industrial results to be obtained that would otherwise have to be sought in very specific environments on the planet, given that real crude oil is produced underground during a millennia-long process of chemical changes.

Liquefaction and condensation

If liquefaction is the transformation, by increasing pressure and decreasing temperature, of a gaseous body into a liquid.

Condensation is the same change of state but under normal conditions of pressure and temperature, that is, condensation is a process that also involves a physical change from gas to liquid, but which occurs without the need to exert enormous pressures, but rather through the decrease in the energy contained in the gas particles.